Centrifugal pump



' F. NEUMANN 'CENTRIFUGAL PUMP Filed Nov. 9, 1923 I Patented Aug. 14, 19211 UNITED STATES PATENT" OFFICE.

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CENTBIIUGAL PUMP.

Application filed November 9, 1928,8eria1 No. 673,815, andin" Germany November 13, 1922.

The connection of air pumps and centrifugal pumps, in such a manner that at the starting a vacuum is produced in the centrifugal pump with the aid of the air pump 5 whereupon t e centrifugal pump is filled with liquid, is known per se.

The water ring pumps, e. g. pumps with circulating packing liquid, are especially adapted to be used as air pumps as they are less sensitive against water hammers and submitted to a lesser wear than the usual piston pumps, the rotating piston pumps and the pumps with slide valves. For starting, a small quantity of water must be generally filled into the water ring pump an tor this water might freeze up so that the pum does not work. Water ring, pumps could therefore hitherto not be used as air pumps for transportable pumps driven by internal combustion engines, especially not for fire pumps. y

This inconvenience is avoided according to this invention by taking the'quantity of water, which is required for the permanent readiness for service for the formation of the rotating liquid ring, immediately before the beginning of the service from the;cool ing liquid for the engine.

As the invention relates specially to pumps designed for fire engines the air pump mustnot only be adapted to be used for the starting of the centrifugal pump but also,'during the service, for exhausting the air which at great suction head will eventually separate. in the suction pipe branch. The water ring pump must further be able to be disengaged during the working of the centrifugal pump when the water flows under pressure into the suction pipe branch of the centrifugalpump. Fire engine pumps must be able to work at' eat suction head aswell as at water admission under ressure. These conditions are fulfilled in t e most simple and eflicient manner by arranging the air pump'on the same shaft as the centrifugal pump and in a common casing. In this case the machine aggregate is furt er of "very compact construction;

In the accompanying drawings an embodiment of the invention 18 shown in Fig. 1 in sectional elevation.

Fig. 2 shows the construction of the improved centrifugal pump with a combustion v engine as used in fire engine pumps.

As shown in Fig. 1 .t e im e1 ers of the centrifugal water pump are eyed on the in wincommon shaft (1 on whichthe rotor c of the air pump is keyed on the suction side. The air pump and the centrifugal pump are arrangedin a common casing whichhas a cooling jacket 6. Two stuifing boxes e,that is not more than for an ordinary centrifugal pump, are used for the packing.

v The water pump communicates with the air pump a through a ringshaped passage I: in the partition wall which separates the water ump from the air pum An outflow :1 rom the lowest point of t e air ump 0 is normally closed by a cock 9. The iighest point f of the suction pipe branch of the water pump communicates through. apoint I: in the partition wall with the air pum 0. Above the pump casing a three way coc a is arranged from which leads a pipe 0 to a water reservoir 0 arranged on the engine, a pipe 1' to the cooling jacket I; and a pipe w to the highest point of the air pump a.

When starting the centrifugal pump the three waycook a, which may be connected or coupled with the control element which in fire engines is provided for the difierent conditions of service or with the, element for the engaging or disengaging of the heating and cooling jacket I), is adjusted so that communica ion between the cooling jacket I) and the air pump -c is established and'it remains in this position until the quantity .of liquid which is required for the starting of the water ring pump has flowed from the cooling jacket 6 into the water ring ump a which then produces the vacuum in t e 'centrifugal pump.

If the water ring pump continues to run after the starting of the centrifugal pump, .theair which eventually separates 1n the suction branch pipe at great suction head is sucked off through the passage is. In this manner a scraping off or a reduction of the delivery at great suction head is avoided.

If, however, aswill generally be the case with fire engines in towns, the water is supplied to the suction pipe branch of the centrifugalpump under pressure the air pump is notrequired. It would merely increase the demand ofenergy as it cannot be uncoupled but rotates with the centrifugal pum Con uently the cock g, which may also couple with'other control elements, is opened whereby the air pump is emptied, which now does no lon er rotate in the water but 'in air and requires only very little energy. Any damaging of the air pump by running dry is excluded as through the gap it which surrounds the shaft d a small quantity of water can always flow into the air pump and serve for the lubrication of this pump before it flows out.

As shown in Fig. 3 the motor fire brigade vehicle comprises the centrifugal pump m,

the water ring pump at and the water reservoir 0. In a slmilar manner as in the first embodiment of the invention a pipe 7 adapted to be shut off by a three way cock :2: leads from the centrifugal pump to the water ring pump n so that this water ring pump can be fed at any time with cooling liquid from the combustion engine 8. The water ring pump n is further connected with the water reservoir 0 by a pipe 0 adapted to be shut off by cock at. The water can therefore be supplied to the .water ring pump either through, the pipe 7' from the cooling jacket of the combustion engine 8 or through pipe 11 from the water reservoir, or, if cock m is adjusted accordingly fresh water is fed from reservoir 0 into the cooling jacket.

The water pump is not in communication with the atmosphere through port It and cock g, when cock 9 is open, the water flowing out of the air pump fills this cock which is closed immediately after all the water has flowed out of the air pump. If cock g is closed the water pump is not open to the atmosphere through It.

I claim 1. The combination with a centrifugal fire engine pump, a water ring sealed air pump for priming said centrifugal pum a driving motor operatively connecte to said pumps for driving said pumps and a container for containing cooling water for said driving motor, of a pipe connected to said water ring pump and said cooling water container, for enabling hot water to be supplied from said container to said water ring ump for forming the liquid ring in the atter, as set forth.

2. The combination with a centrifugal fire engine pump, a water ring sealed air pump for priming said centrifugal pump, a driving motor operatively connected to said pumps for driving said pumps, 0. container or containing cooling water for said driving motor and a water reservoir, of a pipe connected to said water ring pump and said cooling water constructed for enabling hot water to be supplied from said container to said water ring pump and a pipe connected to said water ring pump and said reservoir for enabling cold water to be supplied to the water ring pump from said reservoir, as set forth.

3. The combination with a centrifugal fire engine pump, a water ring sealed air pump for priming said centrifugal pump, a driving motor 0 eratively connected to said pumps for driving said pumps, a container for containing cooling Water for said driving motor and a water reservoir of a three way cock, a pipe connected to said water ring pump and said three way cock, a pipe connected to said cooling water container and said three way cock and a pipe connected to said reservoir and said three way cock, for enabling water to be supplied to the water ring pump from the said cooling water container or from said reservoir, or from said reservoir to said cooling water container, as set forth.

4. The combination with a centrifugal fire engine pump, a water ring sealed air pump for priming said centrifugal pum a driving motor operatively connecte to said pumps for driving said pumps, a container or containing cooling water for said driving motor, of a pipe connected to said water ring pump and sald coolin water container for enabling hot water to e supplied from said container to said water ring ump for formin the liquid ring in the atter, an outlet in the water sealed air pump at the lowest point thereof for enabling the water to be emptied from said pump and a cock for closing said outlet, as set forth.

In testimony whereof I affix m signature.

FRITZ NE NN. 

